13474 research outputs found
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Design concept of in-pipe hydro system prototype for renewable energy generation: Vertical axis parallel turbines / Muhammad Fazrin Abdullah
No full textA new design concept for in-pipe hydropower generation is proposed to optimally
harness power from the flowing water in a pipe without having to fully block or divert
the main water flow, while at the same time makes maintenance work doable without
having to stop the whole operating system. The experiment was first conducted to
evaluate the performance of the specially designed nozzle and turbine set to get the most
optimum performance, using a water pump with a flow rate of 0.48 m3/min. After
getting the most optimum condition for the nozzle and turbine set, the actual prototype
was fabricated based on a water pipe of 5-inch diameter. The prototype was then tested
using a water pump with a maximum flow rate of 4.4 m3/min and maximum water
pressure of 1.4 Bars. The maximum value of water pressure is measured by fully closing
the pipe while running the water pump at maximum speed. The speed of the water pump
is adjustable using a variable speed drive (VSD). Under the best condition, the
differential pressure at P1 (The value of water pressure before the prototype) and P2
(The value of water pressure after the prototype) was 0.29 Bars. The percentage of
pressure loss or the ratio between the value of pressure (P1 – P2) and the total pressure
inside the pipe was 20.7%. The electrical power generated from the in-pipe hydropower
system was 1 kW. Based on the study, the in-pipe hydropower system developed here is
proven to be workable for inpipe hydropower generation. At the same time, the system
can also act as an alternative for a pressure relief valve (PRV)
Non-traditional component of metabolic syndrome in children with obesity: Assesment of TG:HDL-C ratio as insulin resistance component / Nur Zati Iwani Ahmad Kamil
No full textPaediatrics metabolic syndrome (MetS) is on the rise parallel to the increased
prevalence of childhood obesity. Although insulin resistance (IR) is an important
variable in the diagnosis of MetS, the existing paediatric definition of MetS only
measures elevated fasting blood glucose (FBG). Arguably, many children with severe
IR can still regulate their FBG, especially in children with obesity. Therefore, this
study aims to assess the utility of triglyceride to high-density lipoprotein-cholesterol
(TG: HDL-C) ratio as an IR marker in the modelling of paediatric MetS among children
with obesity using structural equation modelling (SEM). This is a cross-sectional study
in which the cross- sectional baseline data of children with obesity participated in the
main MyBFF@school programme, a school-based, cluster randomised controlled trial
(C-RCT) study were sub- analysed. A total of 524 children were selected from 1255
children with obesity (age 10 to 16 years old) who have completed their anthropometric
measurements including waist circumference (WC). Both exploratory (EFA) and
confirmatory factor analysis (CFA) were used to examine TG: HDL-C ratio as an IR
marker in paediatric MetS. This study compares and evaluates two competing four�factor models for each of the first and second order-construct that consists of four core
components (obesity, lipids, IR, and blood pressure) of MetS with changed
variables to the IR factor. Model 1 used FBG, homeostatic model assessment for
insulin resistance index (HOMA-IR), and insulin as an IR factor whereas in Model
2, FBG is substituted with TG: HDL-C ratio. Additionally, one model was
included (model 3) consisting of Leptin: Adiponectin ratio (LAR) which
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is an obesity-IR marker as a reference model. Majority of the children (≈60%) were found
to be abdominally obese. The overall prevalence of MetS was 6.9% (n=36) although about
40% of the children had IR and ≈60% had acanthosis nigricans. This result highlighted
the presence of cardiometabolic risk and a high prevalence of IR in children with obesity.
The TG: HDL-C ratio (standardised factor loading = 0.904) group with HOMA-IR
(standardised factor loading = 0.664) indicated a strong correlation to the IR factor.
Additionally, all MetS factor structures showed an excellent fit with the children with
obesity data. Model 2 (TG: HDL-C ratio) of the first order constructs showed comparable
model fitness indices Goodness of Fit (GFI), Akaike’s information criterion (AIC), and
Bayes information criterion (BIC) with LAR. The least model fit was seen when using
FBG as an IR surrogate. TG: HDL-C ratio performed better as IR surrogate in MetS
structures (standardised factor loading = 0.39) compared to FBG (standardised factor
loading = 0.27). Replacing FBG with TG: HDL-C ratio improved the MetS structure
modelling in children with obesity. Furthermore, the model consisting of TG: HDL-C
ratio was comparable with the reference model consisting of LAR. This study provides
and extendsthe evidence for future use of TG: HDL-C ratio as an alternative for a primary
clinical indicator to select children with obesity at a higher risk for MetS.
Keywords: paediatric; obesity; metabolic syndrome; TG: HDL-C ratio; insulin resistanc
Understanding and assessing dental anxiety and fear in Malaysia / Rashidah Esa
No full textDental anxiety refers to a vague, unpleasant feeling that something undesirable awaits
whereas dental fear is a normal response to a threat or danger. Anticipation of a dental
visit can induce dental anxiety whereas the most fear-provoking situations were the sight
of injection needles and the drilling procedures. Nevertheless, the terms are often used
interchangeably. Dental anxiety and fear (DAF) are perpetual problems worldwide and
their assessment is important to assist dentists in the management of highly anxious
patients. In Malaysia, more studies are needed to add to the growing body of DAF
research. The aim of this thesis was to explore different aspects of DAF and their
associated factors among adolescents, ante natal mothers, preschool children and their
mothers. A series of study was conducted to achieve the aim. In the ante natal study, 407
mothers from Negeri Sembilan participated. The adolescent study comprised of 503, 16-
year-old schoolchildren from Penang. In both these studies, the questionnaire consisted
of participants� demographic profile and the Kleinknecht�s DFS. Two separate studies
were conducted to assess the psychometric properties (validity and reliability) of the
Malay-Early Childhood Oral Health Impact Scale (Malay-ECOHIS) and the Malay
Modified Child Dental Anxiety Scale (Malay-MCDASf).In the mother-child dyad study,
842 complete data were obtained from 24 kindergartens in two districts in Selangor.
Mothers answered the questionnaire on socio-economic status, the Malay-Modified
Dental Anxiety Scale (Malay-MDAS), and the Malay-ECOHIS to assess maternal
perception of impact on child�s oral health-related quality of life (COHRQoL). Child's
dental anxiety was assessed using the Malay-MCDASf. The clinical examination
consisted of the DMFT/dmft as the outcome measure of dental caries disease and
treatment experience.
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The overall prevalence of dental fear among ante natal mothers was 94.1%. However,
67.6% had low fear, whilst 26.5% were moderately fearful. Among 16-year-old
adolescents, 46.7% were moderately fearful and the mean DFS score was 40.8. None of
the ante natal mothers and adolescents reported high fear. The prevalence of high dental
anxiety in the sample of mother-child dyads were 8.7% and 53.9% respectively.
Significant relationship between dental anxiety and dental decay experience in
adolescents, antenatal mothers and mother-child dyads were established. Dentally
anxious participants had more dental decay and higher overall DMFT/dmft. Adolescents
from rural areas reported having significantly higher fear. Maternal dental anxiety and
child dental caries showed significant impact on COHRQoL, child impacts section (CIS)
and family impacts sections (FIS). Demographic factors such as education, income,
urban/rural location, and public/private kindergarten acted as moderators that modify the
strengths of the maternal dental anxiety-COHRQoL relationship. However, child dental
anxiety does not have any significant direct impact on COHRQoL, CIS, FIS, or child
dental caries.
In summary, DAF is quite common among all the studied populations. The prevalence
of child dental anxiety was high. Treating DAF at an early age can produce positive
outcomes and improve the quality of life. There is a need to establish the norms cut-off
points for the different DAF indices. Future research requires development of more
complex models to further understand the dynamics of DAF and their associated factors.
Keywords: dental anxiety, dental fear, dental caries, psychometric, quality of lif
Trends and predictors of glycosylated haemoglobin A1C, blood pressure, and LDL-Cholesterol among patients with type 2 diabetes in Negeri Sembilan, Malaysia / Wan Kim Sui
No full textCardiovascular disease and diabetes pose enormous disease burdens globally and in
Malaysia. Concurrent attainment of glycosylated haemoglobin A1C, blood pressure (BP),
and LDL-cholesterol (LDL-C) goals, or collectively known as the “ABC” goals, help
prevent cardiovascular complications in patients with type 2 diabetes (T2D). Numerous
studies have reported suboptimal achievement of all three ABC goals, and clinical inertia
in diabetes management is one primary reason for poor A1C control. However, such
information is lacking in Malaysia. Hence, this study aims to: a) determine the proportion
of T2D patients who achieved all three ABC goals at study baseline and exit and the
associated factors in Negeri Sembilan, Malaysia; b) describe the A1C, systolic BP,
diastolic BP, and LDL-C trends from 2013 to 2017 and determine the predictors of these
trends; and c) determine the time to treatment intensification and the factors associated
with treatment intensification in patients with uncontrolled A1C. A five-year
retrospective open cohort study from 2013 to 2017 was conducted using data from the
National Diabetes Registry, where six different datasets were merged to form a cohort
dataset. Multivariate binary logistic regression was used to determine the factors
associated with the attainment of all three ABC goals at the study baseline. Interval�censored proportional hazards modelling was carried out to determine the factors
associated with the achievement of all the ABC goals at cohort exit. Meanwhile, linear
mixed-effects modelling was conducted to describe the A1C, systolic BP, diastolic BP,
and LDL-C trends and determine the trends’ predictors. Life table survival analysis was
carried out to determine the time to treatment intensification among patients with
uncontrolled A1C. Proportional hazards modelling was used to determine the factors
associated with treatment intensification. The attainment of all three ABC goals had
improved from 4.5% to 5.8% (P <0.001) but remained suboptimal. Blood pressure was
the limiting factor in achieving the triple targets as only 22.3% to 24.1% of patients
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achieved the BP goal. During the study period, the A1C and systolic BP trends had
worsened (P <0.001 for both). The A1C excess of 1.07% in 2017 represented about 22%
higher risk of diabetes-related death, myocardial infarction, and stroke, which were the
biggest potentially avoidable CVD burdens among the three ABC parameters. Although
the LDL-C trend improved consistently from 2.97 to 2.77 mmol/L, the mean values were
still above the treatment goal of <2.6 mmol/L. Clinical inertia in T2D management was
evident. The median time to treatment intensification was more than one year, and less
than 50% of patients with uncontrolled A1C had treatment intensification. There were
demographic differences whereby non-Chinese ethnic groups and younger adults had the
most inadequate control of ABC. Higher body mass index categories and more intense
treatment modalities were independent predictors for poorer ABC outcomes.
Opportunities exist for further improvement as targeted interventions can be directed at
the identified high-risk populations. More studies are needed to explore the underlying
causes of clinical inertia in Malaysia so that effective strategies can be developed to
address this issue.
Keywords: blood pressure, cholesterol, clinical inertia, glycosylated haemoglobin A1C,
type 2 diabete
Scientometrics assessment of Malaysian social science research in the web of science (2007-2017) / Siti Khairiha Ibrahim
No full textPrevious studies mostly have looked into the growth of science-based research and there has been limited empirical work carried to look into the research performance including publication productivity and impact of Malaysian Social Science Research Systems. Therefore, the purpose of this study is to explore the research performance using scientometric assessment of Malaysian Social Science Research in the Web of Science (WoS) over the period of 11 years from 2007 to 2017 at the meso and micro levels. This study covers the discipline's productivity, impact and publication patterns. The research questions posed are (a) What is the growth of Malaysian Social Science Research literature in the Web of Science over the period of 2007 - 2017? (b) What is the scientific performance of Malaysian Social Science Research in the Web of Science at the meso and micro level? (c) What is the research impact of Malaysian Social Science Research in the Web of Science at the meso and micro level? and (d) What are the characteristics of the journals that Malaysian Social Science researchers published in? A total of 9929 publications retrieved from the Web of Science Core Collection database over the period of 2007 to 2017 covered in the Social Science Citation Index (SSCI) is used for to answer the research questions posed. Based on search criteria used which is “Malaysia” in address and “Article” in type of document, 6249 records were retrieved and used for analysis. The analysis of trends, profiles in publication and citation patterns explore the strength of different research areas. The findings indicate that the publication of Malaysian Social Science research in the WoS has been increasing since 2008. The most productive institution and social scientist are both from the Universiti Malaya. University Tunku Abdul Rahman has the highest total citation per paper over the period of study. One of the characteristics of WoS indexed journals that published Malaysian Social Science research is obviously the international commercial publishers as the coverage of Malaysian social science journals in WoS is only limited to the Malaysian Journal of Library & Information Science. The finding of this study found that the overall publication and citation of Malaysian Social Science research in the WoS have a positive growth in the duration of the study. The study may provide a better insight of research evaluation decision in terms of the award of research grant, staff promotion and staff recruitment considering publications in the core literature
Retinal vessel segmentation in fundus images using deep learning / Chen Chun Hui
No full textRetinal vessel is the only microvascular system that can be viewed from digital fundus cameras directly and non-invasively, they are closely relative with human blood circulation, so the appearance and change of retinal blood vessels can reflect cardiovascular and cerebrovascular diseases, such as diabetic and hypertensions. In practice, observing retinal blood vessels has become a crucial step for ophthalmologist to make diagnosis and conduct timely treatment. However, retinal vessels in fundus images are difficult, tedious and time-consuming to recognize for ophthalmologist. Hence, computer-aided diagnosis was introduced to make automatic retinal vessels segmentation. Deep learning is used as it is a promising technique since its high efficiency and accuracy. In this project, we proposed a new method to conduct automatic retinal vessel segmentation. Firstly, we enhanced the quality of raw fundus images by using image processing technique, which the pre-processed images present a better quality than before. Secondly, we proposed a deep-learning based model to make predictions. Inspired by U-net and ensemble learning, our model is comprised of two cascaded U-shaped networks, and each of the sub-network is composed of CBR (Conv., BatchNormalization, ReLU) blocks. The second sub-network aims to fine-tune coarse vessel maps produced by the first sub-network, since it learns features from combination of coarse vessel map and raw input. To enlarge the receptive field, dilation convolution was adopted with whose dilated rates arranged deliberately to make dense sampling. In addition, residual learning was adopted to ease the optimization and sufficient skip connections were added between the two sub-networks to make full use of feature maps. Finally, three public databases were chosen to verify the proposed model and compared its performance with other recent publications. The model produced an accuracy of 0.9552/0.9699/0.9642, an AU_ROC of 0.9787/9852/9846, a sensitivity of 0.8211/0.8466/0.8395 on DRIVE, STARE and CHASE_DB1 databases, respectively. Cross-validation was also conducted to evaluate the generation capacity of the proposed model. In these intensive experiments, the proposed model can produce a good performance after training, so it can provide a good reference for ophthalmologist to perform diagnosi
Factor analysis on spur gear failure using computational simulation / Emilia Norazmi
No full textSpur gears are purported to be the most well-known and simplest gear as compared to other type of gears. Spur gears are also said to be regularly used in series to avoid from using massive size gear. The utilisation of spur gears is basically to shift movement from one shaft (tube) to another shaft that are similar or parallel. Due to deemed as the simplest gears of all gears, spur gears hence are widely applied in most of daily utilised devices and machine such as clocks, washing machines, blenders, kitchen mixers and even music equipment i.e. musical box. To ensure that the musical box can operate and emit a melodious and soothing sound, spur gears are one of the main components in it. Nevertheless, the musical box is criticised to be easily damaged, and the damage is often caused by the destruction of the spur gears encompass the device. In lieu of that, this study will involve the study of spur gears in the musical box that is intended to fill the literature gap. It is hoped that the findings and results from this study can contribute new knowledge in the field of mechanical, specifically on the mechanism of the spur gear. Apart from that, it is also hoped that the result from this study will be able to draw the baseline information on the effect of stress on spur gears towards the performance of the musical box
Recreation of water-cooled exhaust manifold to improve exhaust gas recirculation / Muhammad Irfan Asha'ari
No full textThe exhaust manifold is a component of the common internal combustion engine designed to help flow the exhaust gases away from the cylinder. Usually attached onto the cylinder head with gaskets, nuts and bolts; modern technology has made it possible to integrate the exhaust manifold into the cylinder head. This results in a reduction of cost to manufacture or outsource gaskets, nuts and bolts; lower weight, volume and size; improved fuel consumption; and improved warm-up times from initial start-up. A functional method of improving emissions of an internal combustion is the introduction of recirculated exhaust gases for combustion. The system that incorporates this concept is called Exhaust Gas Recirculation. Traditionally, hot exhaust gas is fed into an EGR valve which regulates the amount of EGR into the intake of a diesel engine. This results in the reduction of NOx emissions due to the lower combustion temperature. Another use of EGR is to cool it and then introduce into the intake. This leads to an increase of engine efficiency due to the lower density of the air-fuel mix. However, modern Spark-Ignited engines have started to incorporate EGR to improve fuel consumption, part-load throttle performance and emissions. Modern engines also incorporate turbocharging, this therefore leads to further design variations in cooling the temperature of exhaust gas. This paper discusses the application of Exhaust Gas Recirculation, Cooled Exhaust Gas Recirculation, Integrated Exhaust Manifold and its concepts to recreate an exhaust manifold suitable for retrofitting onto existing engines of various applications. This exhaust manifold aims to reduce exhaust gas temperatures for the applications stated above to reduce heat transfer and stress on other existing systems while improving fuel consumption and emissions. This reduction in heat transfer to the other components in the engine bay can be attributed to the flow of fluid in the water-cooled exhaust manifold which extracts heat from the walls of the exhaust ports and into the fluid which will then be cooled by a radiator
Design and evaluation of a novel hip prosthesis integrated with a truss system / Darshan Namasivayam
No full textPost-operative fractures after a total hip arthroplasty (THA) are a major concern for
patients. Among the factors contributing to the occurrence of these fractures are limiting
fixation of the prosthesis, prosthesis stability as well as poor bone stock. Most postoperative
fractures that occur after a THA are caused by the revision surgery due to
prosthesis failure. Hence, implant design plays a major role in preventing such fractures.
This study focuses on the design of a novel hip prosthesis that has the capability to
distribute the stress through the prosthesis truss system without inducing additional
stresses to the femur. The first stage of the study consisted of designing a novel prosthesis
by varying three geometrical parameters namely truss angles, caput-collum-diaphyseal
(CCD) angles and femur inclination angles to obtain a design with the best mechanical
characteristics, i.e., the one that gives the lowest stress during typical dynamic activities
such as walking, jogging, and cycling. From finite element simulation, it was found that
the prosthesis design with the inclination angle of 20°, truss angle of 40° and CCD angle
of 132.1° appears to give the lowest von Mises stress. The second stage of the study
focused on evaluating the life cycle and safety factor of the proposed hip prosthesis that
possessed the best characteristics. For this purpose, the maximum and minimum von
Mises stresses at the critical location of prosthesis during each cycle of the dynamic
activities are identified using finite element simulation. The Goodman relation is then
used to estimate the prosthesis life cycle. The results show that the estimated lives were
within an acceptable range. In the last stage of the work, the stress distributions in the
femur during walking and jogging activities were evaluated. Two cases were investigated:
(i) normal femur, i.e., the one without prosthesis and (ii) femur combined with the
proposed prosthesis. Results showed that the addition of the proposed prosthesis reduced
the stresses in the femur. These findings highlight the strength of the proposed prosthesis
Multi-array sensorised pillowcase as call detection alarm system for in ward tetraplegic patient / Normazlianita Mohamad Alias
No full textCall bell systems play an important role for patients and nurse interaction in hospitals
and at homes. Conventionally, when in danger or in need, a patient would press a call
bell button for assistance. However, a large percentage of hospitalized patients are unable
to use such device due to hand weakness or the device is unreachable to the patient when
positioned away, especially for patients with tetraplegia. This problem has motivated the
development of a fabric-based multi-array pressure sensor as a call bell garment that
works by detecting the pressure pattern on a pillow surface where the patient is lying
down. In this study, we utilized off-the-shelf materials to form: i) a fabric-based multiarray
pressure sensor system, ii) an acquisition circuit along with interface and signal
processing algorithms to acquire and interpret the sensor data. To ensure the functionality
of the proposed fabric-based pressure sensor, a colour-coded mesh plot was developed to
visualise the sensor data. The reliability of the sensor was tested using a portable load
cell. Pressure profile of the proposed multi-array fabric-based pressure sensor shows
comparable profile to that of the commercialized pressure sensor. The main advantage of
the proposed sensor is that it is flexible and adaptable making it suitable to be interfaced
with the human body. A case study was performed on an able-bodied person and two
tetraplegic patients who used the sensor as the pillow cover. Findings from this case study
have demonstrated the ability to map the force on the surface of the pillow and
subsequently the location of the force applied with 71% accuracy and 70% sensitivity.
This feature makes it suitable to detect the pattern of head movement and hence a call bell
for patients with special needs